package homework;

import java.math.BigInteger;

/**
 * ..... 作业
 */
public final class BigInterTools  {

    public static BigInteger add(String s1, String s2) {
        BigInteger b1 = new BigInteger(s1);
        BigInteger b2 = new BigInteger(s2);
        return b1.add(b2);
    }

    public static BigInteger subtract(String s1, String s2) {
        BigInteger b1 = new BigInteger(s1);
        BigInteger b2 = new BigInteger(s2);
        return b1.subtract(b2);
    }
}